Eliminating torsional vibration in a rotating shaft is an important consideration in the transmission of energy. Many modern systems rely on a rotating shaft to deliver kinetic energy from a motor (e.g. combustion engines). Such a shaft is susceptible to torsional vibrations having a frequency of vibration that is a natural multiple of the shaft angular velocity. In many cases these vibrations arise in the motor, and are a result of periodic combustion procedures therein. These vibrations are undesirable due to associated noise and/or equipment fatigue.
One known solution to the vibration problem is the use of a dual mass flywheel. Such a flywheel acts as a pre-tuned resonant damper. However, a pre-tuned damper is not effective for dampening harmonics at variance with its resonant frequency. This is not optimal, especially for undesired harmonics having frequencies that vary with shaft angular velocity. Further, such a flywheel delays the response to the desired generalized force of rotation.
U.S. Pat. No. 6,217,475 Dual-Mass Variable Inertia Flywheel Assembly discloses a vehicle driveline system includes a planetary gear arrangement that cooperates with a flywheel member to provide a dual mass variable inertia flywheel assembly. The planetary gear arrangement preferably includes an automated actuator that selectively engages different portions of the planetary gear arrangement to provide at least two operating positions that each has an associated effective mass and a corresponding moment of inertia. Choosing an operating position selectively controls the inertia of the flywheel assembly and greatly reduces or eliminates torsion vibrations that may otherwise occur. The first and second operating positions also provide high and low range transmission operation, respectively. This solution, however, does not provide for a damper that is responsive to the varying shaft angular velocity.
U.S. Pat. No. 6,192,851 Vibration Reducing System For Internal Combustion Engine discloses a vibration reducing system of an internal combustion engine for an automotive vehicle. The vibration reducing system comprises a roll vibration system which generates a roll vibration of an engine main body, the roll vibration having a first vibration mode. Additionally, a rotational vibration system is provided to generate a rotational vibration having a second vibration mode, and includes a crankshaft of the engine, for generating a rotational driving force, a main flywheel fixedly connected to the crankshaft, a driving force transmitting mechanism through which the rotational driving force of the crankshaft is transmitted, the driving force transmitting mechanism being movably secured to the engine main body, and an inertial mass member drivably connected to the driving force transmitting mechanism and rotatable to generate an inertial force upon receiving the rotational driving force transmitted through the driving force transmitting mechanism. In the vibration reducing system, the first and second vibration modes cause anti-resonance at an anti-resonance frequency. Additionally, the rotational vibration system is adjusted to cause the anti-resonance frequency to be generally coincident with one of frequencies which are obtained respectively by multiplying an engine-revolution frequency at a predetermined engine speed by values each being represented by (a natural number/2). This solution is directed at countering engine vibration, not torsion vibration of the shaft.
U.S. Pat. No. 5,733,218 Flywheel Having Two Centrifugal Masses And A Torsional Vibration Damper With Gear Train Elements Which Can Be Adjusted As A Function Of Load discloses a torsional vibration damper has an input-side transmission element and an output-side transmission element, at least one of which is connected, preferably by means of a spring device, with at least one moment-transmitting element of a gear train which acts between the two transmission elements. At least one of the moment-transmitting gear train elements can be aligned before the creation of a connection to the corresponding element with some play, or clearance, at least in the radial direction, with respect to this element carrier, and after the application to the gear train of an adjustment moment which effects an alignment of this transmission element with respect to the other transmission elements as a function of the force by moving the two transmission elements into a predetermined relative position, the gear train element in question can be provided with a connection to the element carrier which fixes the element in its position where it has been aligned as a function of the force. This disclosure also fails to address dampers that are responsive to the varying shaft angular velocity.
U.S. Pat. No. 5,720,248 (EP 586 973 B1) Torsional Tunable Coupling For Diesel Engine Drive Shaft discloses an improved coupling assembly is provided for transmitting rotary power from the working end of an internal combustion engine to a driven shaft. The crankshaft also has a free end connected to an accessory drive train. The coupling assembly comprises a low inertia flywheel having a mass so selected as to cause the node of the first crankshaft mode of torsional vibration to be located in the vicinity of the middle of the crankshaft, and a flexible coupling which interconnects the working end of the crankshaft with the driven shaft. The low inertia flywheel not only reduces the amplitude of the torsional deflection at the free end of the crankshaft, but further raises the primary torsional vibration orders of the engine which excite the coupling assembly by at least one half of an order such that the peak stresses applied to the teeth of the first gear wheel of the accessory drive train are at least halved and are further applied to at least twice as many gear teeth, thereby greatly prolonging the life of the gear wheel. Moreover, the low inertia flywheel further increases the lifetime of the flexible coupling by raising its natural frequency to a level which is substantially higher than the 0.5 engine order of torsional. vibration associated with engine malfunction and governor interaction. This disclosure does not address dampers that are responsive to the varying shaft angular velocity.
U.S. Pat. No. 5,570,615 Arrangement For Balancing Varying Moments And Vibrations In A Motor Vehicle Drive Train discloses technology to balance varying moments and reduce vibrations in the drive train of a motor vehicle. Three flywheel masses and a clutch are provided in a common housing. Two flywheel masses are connected by springs to provide a dual-mass flywheel for reducing vibrations which can be transmitted into the transmission from the crankshaft and the third flywheel mass is connected to the first flywheel mass by planet gears mounted in fixed relation to the housing so that the direction of rotation of the third flywheel mass is opposite to the direction of rotation of the crankshaft. This disclosure is also directed at a pre-tuned solution, not at a responsive, self-tuning solution.
U.S. Pat. No. 5,493,936 Two-Mass Flywheel discloses a two-mass flywheel including a device that in series with a slip friction clutch couples a secondary mass rotationally-elastically to a primary mass. The slip friction clutch includes two side disks, similar to cup springs, that engage opposite faces of a center disk at the same effective diameter. The two side disks are preassembled to make a subassembly in which the spring preload can be adjusted after assembly. This is another pre-tuned solution.
EP 349 624 Device For Suppressing Noise And Vibrations, In Particular In Continuously Variable Transmissions With Powers Split In Motor Vehicles discloses a device for suppressing noise and vibration in continuously variable transmissions with power split in motor vehicles. The power is split into two branches, one of which passes through a continuously variable converter. Said converter is insulated from the whole housing by means of special noise- and vibration-suppressing elements. The noise-producing torsional vibrations of the converter unit are also reduced to a minimum by a multi-weight flywheel system. This solution does not propose to overcome the aforementioned limitations of a pre-tuned multi-mass damper.
Application JP 2001057882 Vibration Damping Flywheel With Double Mass In Automobile discloses a vibration damping flywheel with a double mass in an automobile capable of buffering shock of output torque of an engine and damping twisted vibration of a driving system by means of the double mass. The vibration damping flywheel with the double mass in the automobile comprises a flywheel with a primary mass and a secondary mass, a compressed coil spring, in which two sets of the compressed coil springs respectively located in an inner side and outer side are filled up by grease, for improving damping effect in order to improve buckling prevention and durable strength, a drive plate capable of flexibly realizing a hysteresis curve of the spring by compressing the coil spring while rolling on the compressed coil spring and by adjusting the shapes by means of an ax-shaped die or arch-shaped die, a roller for compressing while the drive plate is rotating itself and also rolling on the spring, and a spring guide capable of supporting a compression type coil spring. This application does not address the issue of pre-tuning deficiencies.
Applications JP 10018523 and JP 10018513 Device Having Buffer Device Laid Between At Least Two Flywheel Mass Bodies Capable Of Relatively Turning For Each Other disclose making the turning resistance of a buffer device variable for the number of revolutions or a centrifugal force, and installing a pressure accumulator effective in a peripheral direction and a pressure accumulator effective in an axial direction. Pre-tuning limitations are also inherent in this technology.
Application JP10018523 discloses a flywheel wherein the axis of abscissa relates to a turning angle across the flywheel mass bodies, while the axis of ordinate shows the transmissible moment of an elastic torsional vibration damping device and a transmissible moment via a slide clutch relates to the centrifugal force of a friction means. The coil spring of the damping device is somewhat compressed, due to the relative turning motion of the flywheel mass bodies from the non-acting position thereof. Moment generated continues until becoming equal to the slide moment of a friction means. Then, this friction means slips to a turning angle, due to turning in the same direction. When the means slips, exceeding the angle, the spring is further compressed, and a block is formed after the passage of the means through a turning angle range. Furthermore, when moment exceeds a value transmissible via the friction means, the flywheel mass bodies become capable of giving a relative turning motion. As a result, the variation of the moment can be dampened or eliminated. This technology is not applicable to problem of per-tuning.
In application JP10018513, an intermediate plate of the output part of a friction slide clutch forms the input part of a buffer device, and the buffer device has a first disc and a second disc at both sides of the intermediate plate. The first and second discs are connected to a rotary mass body at an axial gap in such a state as incapable of turning. Also, a pressure accumulation member made of a coil spring is housed in the windows of the zone of the intermediate plate, and the coil spring acts against the relative rotation of the intermediate plate, and the first and second discs. In addition, a friction device is laid between first and second rotary mass bodies in parallel with the spring, and at a position between the first disc and the zone of the first rotary mass body in an axial direction. Thereafter, the friction device is set and tightened between the disc and a crimp ring, and a friction ring is laid between the crimp ring and the zone in an axial direction. Also, the crimp ring is peripherally fixed to the first disc. According to this construction, a vibration can be dampened. This technology is also inapplicable to the problem at hand.
Application JP 06165698 Crankshaft Device For Two-Cylinder Four-Cycle Engine, is directed to reduce energy loss even in the case that massive error occurs at balance weights when a crankshaft alone is balanced, by easily adjusting the massive error afterward, and reducing the mass of a second balance weight. A fan driving pulley and a flywheel are fixed to a crankshaft in which a crank angle of 180 degrees are shown between a first crank pin and a second crank pin. A first balance weight which suppresses a vibration moment of the crank shaft is arranged on a crank arm on one end side of the crankshaft. A second balance weight is arranged on a flywheel fixed to the other end side of the crankshaft. This flywheel technology is not addressed to overcome pre-tuning limitations.
Patent JP 2588838 Belt-Type Continuously Variable Transmission is directed to improve vibration reducing performance of a flywheel and durability of its supporting part by variably forming inertia mass of the flywheel in a belt type continuously variable transmission. A drive pulley, provided in a drive shaft connected to an engine through a flywheel, can be connected to the drive shaft through a forward clutch. When a shift range is placed in a stop range with small inertia mass only required for the flywheel, the forward clutch is disengaged. When the shift range is placed in a running range with large inertia mass required for the flywheel, the forward clutch is engaged, and inertia mass in a full line part in the drawing is used to serve as the substantial inertia mass of the flywheel. This technology is also not applicable to overcome pre-tuning limitations.
U.S. Pat. No. 6,427,656, Internal Combustion Engine Including A Means Of Reducing Cyclic Disturbances For Low-Speed Running discloses an invention related to an internal combustion engine, the crankshaft of which is equipped with a pulley or flywheel secured to it by fastening means, in which the flywheel is equipped with at least one pendular element, whose size, mass and position on the flywheel are determined so as to be tuned to close to the angular frequency of the major harmonic of the cyclic disturbance. This technology does address a self-tuning solution. However, the pendulum solutions incorporated therein (Flyweights, Liquid mixtures, etc.) do not comprehensively address all acceleration patterns. Also, the disclosed unattached flyweights or liquid mixtures may not be compatible with other design considerations e.g. engine noise, environmental concerns, etc. Further, the solution disclosed addresses self-tuning multi-mass flywheels for single harmonic annihilation only.
Japanese application 11323776, Rolling Vibration Reducer For Internal Combustion Engine, discloses a rolling vibration reducer for an internal combustion engine. The reducer offers a rolling vibration reducing effect in specified operating conditions even if the inertial mass of a main flywheel system is changed. A rotor portion of a compressor for an air-conditioner, constituting a main flywheel system, is connected to a compressor pulley rotationally driven by an accessory driving belt via an electromagnetic clutch in an approachable/separable manner. A rotating shaft of the rotor portion is connected to the electromagnetic clutch and provided with a torsional spring portion of which spring constant is operated along the direction of the torsion of the rotating shaft. In this way, in rotationally driving the rotor portion, with the operation of the spring constant of the torsional spring portion, the antiresonant frequencies of the vibration of the main flywheel system and the vibration of a sub-flywheel are kept to approximately agree with any of the frequency natural number/2 times of a rotational frequency at the preset rotating speed of a crank shaft. Although this application demonstrates the incorporation of an electromagnetic clutch, it only addresses preset shaft speeds.
Thus, it is not known in the art to provide a damper for shaft torsional vibrations capable of dampening multiple frequencies that are a function of the shaft angular velocity. Nor is it known to similarly dampen single frequencies, except by pendular free flyweights and liquid mixtures. Ideally, the response delay, to the desired generalized force of rotation, of an improved damper is less than that of a dual mass flywheel.